Adaptive scheme for lowering uplink control overhead

ABSTRACT

The present invention is related to methods, apparatuses, systems and computer software for determining an amount of physical resources for downlink transmission, and allocating uplink physical resources for transmission of data-non-associated control signaling based at least on the amount of physical resources for downlink transmission. The amount of physical resources for downlink transmission comprises an amount of downlink control signaling. The present invention further relates to a framework for mapping the dedicated uplink control channels directly to single physical resource blocks. The framework is able to efficiently shift physical resources to and from the uplink control channel for ACK/NACK reports, in a data-non-associated control signaling scheme and on a per subframe basis. The present invention is also concerned with scheduler, for example an eNodeB scheduler, which uses its scheduling history and knowledge of user equipment capabilities to increase utilization of uplink resources.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/456,409, filed on Apr. 26, 2012, which is a continuation of U.S.application Ser. No. 11/906,324, filed Oct. 1, 2007; which claims thebenefit of U.S. Provisional Application Ser. No. 60/849,150, filed Oct.2, 2006.

FIELD OF THE INVENTION

The present invention relates to wireless communication, and moreparticularly to transmission in a Universal Mobile TelecommunicationsSystem (UMTS) Terrestrial Radio Access Network (UTRAN) or long termevolutions of UTRAN.

BACKGROUND OF THE INVENTION

LTE, or Long Term Evolution, is a name for research and developmentinvolving the Third Generation Partnership Project (3GPP), to identifytechnologies and capabilities that can improve systems such as the UMTS.The present invention involves the long term evolution (LTE) of 3GPP.Implementations of wireless communication systems, such as UMTS(Universal Mobile Telecommunication System), may include a radio accessnetwork (RAN). In UMTS, the RAN is called UTRAN (UMTS Terrestrial RAN).Of interest to the present invention is an aspect of LTE referred to as“evolved UMTS Terrestrial Radio Access Network,” or E-UTRAN.

In general, in E-UTRAN resources are assigned more or less temporarilyby the network to one or more user equipment terminals (UE) by use ofallocation tables, or more generally by use of a downlink resourceassignment channel. Users are generally scheduled on a shared channelevery transmission time interval (TTI) by a Node B or an evolved Node B(e-Node B). A current working assumption for LTE is that users areexplicitly scheduled on a shared channel every transmission timeinterval (TTI) by an eNodeB. An eNodeB is an evolved Node B and is theUMTS LTE counterpart to the term “base station” in the Global System forMobile Communication (GSM). In order to facilitate the scheduling on theshared channel, the e-Node B transmits an allocation in a downlinkcontrol channel to the UE. The allocation information may be related toboth uplink and downlink channels. The allocation information mayinclude information about which resource blocks in the frequency domainare allocated to the scheduled user(s), which modulation and codingschemes to use, what the transport block size is, and the like.

An example of the E-UTRAN architecture is illustrated in FIG. 1. Thisexample of E-UTRAN consists of eNodeBs, providing the E-UTRA user plane(RLC/MAC/PHY) and control plane (RRC) protocol terminations towards theUE. The eNodeBs are interconnected with each other by means of the X2interface. The eNodeBs are also connected by means of the S1 interfaceto the EPC (evolved packet core) more specifically to the MME (mobilitymanagement entity) and the UPE (user plane entity). The S1 interfacesupports a many-to-many relation between MMEs/UPEs and eNodeBs. The S1interface supports a functional split between the MME and the UPE. TheMMU/UPE in the example of FIG. 1 is one option for the access gateway(aGW).

In the example of FIG. 1, there exists an X2 interface between theeNodeBs that need to communicate with each other. For exceptional cases(e.g. inter-PLMN handover), LTE_ACTIVE inter-eNodeB mobility issupported by means of MME/UPE relocation via the S1 interface.

The eNodeB may host functions such as radio resource management (radiobearer control, radio admission control, connection mobility control,dynamic allocation of resources to UEs in both uplink and downlink),selection of a mobility management entity (MME) at UE attachment,routing of user plane data towards the user plane entity (UPE),scheduling and transmission of paging messages (originated from theMME), scheduling and transmission of broadcast information (originatedfrom the MME or O&M), and measurement and measurement reportingconfiguration for mobility and scheduling. The MME/UPE may hostfunctions such as the following: distribution of paging messages to theeNodeBs, security control, IP header compression and encryption of userdata streams; termination of U-plane packets for paging reasons;switching of U-plane for support of UE mobility, idle state mobilitycontrol, SAE bearer control, and ciphering and integrity protection ofNAS signaling. The invention is related to LTE, although the solution ofthe present invention may also be applicable to present and futuresystems other than LTE.

In general, E-UTRAN may use orthogonal frequency division multiplexing(OFDM) as the multiplexing technique for a downlink connection betweenthe eNode B and the UE terminal, in which different system bandwidthsfrom 1.25 MHz to 20 MHz are applied. Using OFDM may allow for linkadaptation and user multiplexing in the frequency domain. However, toutilize the potential of multiplexing in the frequency domain the Node Bor eNode B needs to have information related to the instantaneouschannel quality. In order for the Node B or eNode B to be informed ofthe channel quality, the user equipment terminal provides channelquality indicator (CQI) reports to the eNode B. The user equipmentterminal may periodically or in response to a particular event send CQIreports to the respective serving e-Node B, which indicate therecommended transmission format for the next transmission time interval(TTI). The report may be constructed in such a way that it indicates theexpected supported transport block size under certain assumptions, whichmay include, the recommended number of physical resource blocks (PRB),the supported modulation and coding scheme, the recommended multipleinput multiple output (MIMO) configuration, as well as a possible poweroffset.

In general, the interface between a user equipment (UE) and the UTRAN orE-UTRAN has been realized through a radio interface protocol establishedin accordance with radio access network specifications describing aphysical layer (L1), a data link layer (L2) and a network layer (L3).For example, the physical layer (PHY) provides information transferservice to a higher layer and is linked via transport channels to amedium access control (MAC) layer of the second layer (L2). Data travelsbetween the MAC layer at L2 and the physical layer at L1, via atransport channel. The transport channel is divided into a dedicatedtransport channel and a common transport channel depending on whether achannel is shared. Also, data transmission is performed through aphysical channel between different physical layers, namely, betweenphysical layers of a sending side (transmitter) and a receiving side(receiver).

Typically, the second layer (L2) may include the MAC layer, a radio linkcontrol (RLC) layer, a broadcast/multicast control (BMC) layer, and apacket data convergence protocol (PDCP) layer. The MAC layer mapsvarious logical channels to various transport channels. The MAC layeralso multiplexes logical channels by mapping several logical channels toone transport channel. The MAC layer is connected to an upper RLC layervia the logical channel. The logical channel can be divided into acontrol channel for transmitting control plane information, such ascontrol signaling, and a traffic channel for transmitting user planeinformation, such as data information.

Due to the different capabilities of the eNodeB and UE, the downlink(DL) and uplink (UL) physical layers for LTE may be different. Physicalchannels convey information from higher layers in the LTE stack, andphysical signals may be used exclusively for use in the physical layer.Physical channels map to transport channels, which are service accesspoints (SAPs) for the L2/L3 layers. The downlink physical channels arePhysical Downlink Shared Channel (PDSCH), which is used for data andmultimedia transport, Physical Downlink Control Channel (PDCCH), whichconveys UE-specific control information, and Common Control PhysicalChannel (CCPCH), which is used to carry cell-wide control information.There are two types of physical signals, reference signals used todetermine the channel impluse response (CIR), and synchronizationsignals which convey network timing information. The downlink transportchannels are Broadcast Channel (BCH), Downlink Shared Channel (DL-SCH),Paging Channel (PCH), and Multicast Channel (MCH).

In the uplink, the physical channels are Physical Uplink Shared Channel(PUSCH) and Physical Uplink Control Channel (PUCCH), which carry controlinformation such as channel quality indication (CQI), ACK/NACK, HARQ anduplink scheduling requests. The uplink physical signals are uplinkreference signal and random access preamble. The uplink transportchannels are Uplink Shared Channel (UL SCH) and Randon Access Channel(RACH).

In order to facilitate the scheduling on the shared channel, the eNodeBtransmits an allocation in a downlink shared control channel to the userequipment (UE). The allocation information will often be related to bothuplink and downlink. In LTE for example, if the UE is scheduled for bothuplink and downlink transmission the UE may receive two allocationgrants, one for the uplink and one for the downlink. The functionalityof the allocation is in principle similar to the high speed sharedcontrol channel (HS-SCCH), which is used for high speed downlink packetaccess (HSDPA).

The allocation is used to signal which user(s) are going to be scheduledin each TTI. The current default assumption in 3GPP is that theallocation includes information about which resource blocks in thefrequency domain are allocated to scheduled user(s), which modulationscheme to use, what the transport block size is, and the like. Theallocation also often includes various information related to hybridautomatic repeat requests (HARQ).

The current working assumption of an evolved UTRAN is that LTE will beusing Orthogonal Frequency Division Multiplexing Access (OFDMA) as themultiplexing technique in the downlink direction, where multiple userscan be frequency multiplexed in the downlink direction with a single TTI(which will have the duration of two sub-frames, i.e., 1 ms). One of thekey elements for efficient link operation is the utilization of HARQ,such that for each transmitted packet, physical resources will beallocated in the uplink, so that each allocated UE can transmit HARQacknowledgement or negative acknowledgement (ACK/NACK) based on itsreception. The assumption for the downlink is that HARQ is asynchronous,but it is expected that the UE's transmission of ACK and NACK will betime-wise tied to the received transmission. In cases where UE does nothave data to transmit in the uplink at the time of ACK/NACK, a dedicatedphysical control channel is assumed to carry the ACK/NACK bit.Otherwise, the ACK/NACK could also be piggy-backed to the datatransmission. Both the allocation in uplink and downlink is decided andcontrolled by the eNodeB.

The number of users multiplexed in downlink may change significantlyfrom sub-frame to sub-frame. Some of the factors contributing to suchvariations include changes in traffic (burstiness) which means thatvarying number of users have different and fast varying amounts of datato transmit, or properties of radio-aware scheduling that have changesin number of users allocated per sub-frame.

Given that the traffic is asymmetrical (or time-alternating as in thecase of VoIP (Voice over Internet Protocol), it will often happen thatACK/NACK need be sent in uplink as data-non-associated transmission, ortransmission on a separate physical channel tied to the downlinkallocation, for example. Such resources need be reserved and provided ifno adaptive mechanism is available, and we need to allocate theresources according to the worst-case multiplexing amount. This causes aloss in system capacity. Therefore, there is a need to overcome theproblems discussed above.

SUMMARY OF THE INVENTION

The following presents a simplified summary of the invention in order toprovide a basic understanding of some aspects of the invention. Thissummary is not an extensive overview of the invention. It is intended toneither identify key or critical elements of the invention nor delineatethe scope of the invention. Its sole purpose is to present some conceptsof the invention in a simplified form as a prelude to the more detaileddescription that is presented later.

The present invention is related to a framework for mapping thededicated uplink control channels directly to single physical resourceblocks (PRBs). The framework is able to efficiently shift physicalresources to and from the uplink control channel for ACK/NACK reports,in a data-non-associated control signaling scheme and on a per subframebasis. The present invention is also concerned with scheduler, forexample an eNodeB scheduler, which uses its scheduling history andknowledge of user equipment (UE) capabilities to increase utilization ofuplink resources.

When an eNodeB is used to schedule users on a shared channel in atransmission time interval, it allocates the uplink physical resourcesfor ACK/NACK at least partly based on the current amount of the physicalresources for downlink transmission, or the allocation history of thedownlink transmission. The amount of physical resources for downlinktransmission is determined at least partly based on the number of usersand/or the number of packets multiplexed within a downlink subframe in aphysical resource block. The eNodeB is also adapted to allocate uplinkphysical resources for data transmission based on amount of physicalresources allocated for transmission of ACK/NACK reports.

For delayed uplink allocation, the amount of allocated physicalresources for ACK/NACK reports is also estimated based whether some ofthe ACK/NACK reports can be piggy-backed to uplink data transmission.

In accordance with a first aspect of the invention, a method is providedthat includes determining an amount of physical resources for downlinktransmission, and allocating uplink physical resources for transmissionof data-non-associated control signaling based at least on the amount ofphysical resources for downlink transmission. The amount of physicalresources for downlink transmission may include an amount of downlinkcontrol signaling.

In accordance with the first aspect of the invention, determining theamount of physical resources for downlink transmission is at leastpartly based on number of user equipment terminals multiplexed within adownlink subframe in a physical resource block.

In accordance with the first aspect of the invention, determining theamount of physical resources for downlink transmission is at leastpartly based on a number of packets multiplexed within a downlinksubframe in a physical resource block.

In accordance with the first aspect of the invention, the method mayfurther include allocating uplink physical resources for datatransmission based at least on the amount of uplink physical resourcesallocated for transmission of data-non-associated control signaling.

In accordance with the first aspect of the invention, determining theamount of physical resources for downlink transmission is based onwhether the data-non-associated control signaling is at least partlyincorporated into uplink data transmission.

In accordance with the first aspect of the invention, the amount ofphysical resources for downlink transmission comprises physicalresources allocated for current transmission.

In accordance with the first aspect of the invention, the amount ofphysical resources for downlink transmission comprises physicalresources allocated for past transmission.

In accordance with the first aspect of the invention, the user equipmentterminals include user equipment terminals in semi-static locations.

In accordance with the first aspect of the invention, uplink controlchannel boundaries for each of the user equipment terminals areallocated within boundaries of a single physical resource block.

In accordance with a second aspect of the invention, an apparatus isprovided that may include a determiner for determining an amount ofphysical resources for downlink transmission, and an allocation unit forallocating uplink physical resources for transmission ofdata-non-associated control signaling based at least on the amount ofphysical resources for downlink transmission. The amount of physicalresources for downlink transmission may include an amount of downlinkcontrol signaling.

In accordance with the second aspect of the invention, the apparatus mayalso include a recorder for recording a number of user equipmentterminals multiplexed within a downlink subframe in a physical resourceblock, and the determiner is responsive to the number of multiplexeduser equipment terminals for determining the amount of physicalresources for downlink transmission.

In accordance with the second aspect of the invention, the apparatus mayalso include a recorder for recording a number of packets multiplexedwithin a downlink subframe in a physical resource block, and thedeterminer is responsive to the number of multiplexed packets fordetermining the amount of physical resources for downlink transmission.

In accordance with the second aspect of the invention, the allocationunit is configured to allocate uplink physical resources for datatransmission based at least on the amount of uplink physical resourcesallocated for transmission of data-non-associated control signaling.

In accordance with the second aspect of the invention, the determiner isconfigured to determine the amount of physical resources for downlinktransmission based on whether the data-non-associated control signalingis at least partly incorporated into uplink data transmission.

In accordance with the second aspect of the invention, the amount ofphysical resources for downlink transmission includes physical resourcesallocated for current transmission.

In accordance with the second aspect of the invention, the amount ofphysical resources for downlink transmission includes physical resourcesallocated for past transmission.

In accordance with the second aspect of the invention, the userequipment terminals include user equipment terminals in semi-staticlocations.

In accordance with the second aspect of the invention, uplink controlchannel boundaries for each of the user equipment terminals areallocated within boundaries of a single physical resource block.

In accordance with the second aspect of the invention, the apparatus maybe included in or is a network element.

In accordance with the second aspect of the invention, the apparatus mayfurther include a scheduler for scheduling downlink packets, and aprediction module for predicting a number of expected reports based atleast on the amount of physical resources for downlink transmission.

In accordance with a third aspect of the invention, an apparatus isprovided that includes means for determining an amount of physicalresources for downlink transmission, and means for allocating uplinkphysical resources for transmission of data-non-associated controlsignaling based at least on the amount of physical resources fordownlink transmission. The amount of physical resources for downlinktransmission comprises an amount of downlink control signaling.

In accordance with the third aspect of the invention, the apparatus mayfurther include means for scheduling downlink packets, and means forpredicting a number of expected reports based at least on the amount ofphysical resources for downlink transmission.

In accordance with a fourth aspect of the invention, a system isprovided that includes a determiner for determining an amount ofphysical resources for downlink transmission, an allocation unit forallocating uplink physical resources for transmission ofdata-non-associated control signaling based at least on the amount ofphysical resources for downlink transmission, and at least one userequipment terminal responsive to the allocation of uplink physicalresources for transmission of data non-associated control signaling forproviding control signaling according to the allocation. The amount ofphysical resources for downlink transmission comprises an amount ofdownlink control signaling.

In accordance with the fourth aspect of the invention, the system mayfurther include a network element that includes the determiner and theallocation unit.

In accordance with a fifth aspect of the invention, a computer programproduct is provided that includes a computer readable storage structureembodying computer program code thereon for execution by a computerprocessor, wherein said computer program code comprises instructions forperforming a method including the steps of determining an amount ofphysical resources for downlink transmission, and allocating uplinkphysical resources for transmission of data-non-associated controlsignaling based at least on the amount of physical resources fordownlink transmission.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the inventionwill become apparent from a consideration of the subsequent detaileddescription presented in connection with accompanying drawings, inwhich:

FIG. 1 illustrates an exemplary E-UTRAN architecture.

FIG. 2 illustrates an exemplary mapping scheme between dedicated uplinkcontrol channels and the physical resource block (PRB) structure, with12 sub-carriers per PRB.

FIG. 3 illustrates similar exemplification of mapping of ACK/NACKcontrol channel to PRB using a distributed method when several PRBs arereserved for control.

FIG. 4 illustrates an example of the relation between downlinkallocation and required uplink ACK/NACK resources, withdata-non-associated transmission in the uplink.

FIG. 5 illustrates an exemplary method according to an embodiment of thepresent invention.

FIG. 6 illustrates another exemplary method according to an embodimentof the present invention.

FIG. 7 illustrates a block diagram for an apparatus that is configuredto carry out the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Based on the physical resources that may be needed for sending anacknowledgement/negative acknowledgement (ACK/NACK) report, a networkelement, for example an evolved NodeB (eNode B), may reserve asignificant signaling space for each transmission (tied to downlinkpacket transmission). For example, in WCDMA/HSDPA, it is possible to usea factor-10 repetition of the ACK/NACK bit as well as efficientfrequency diversity by spreading. This means that the fading margin israther small for the WCDMA case except when the signaling is in flatchannel conditions.

Depending on the design of the control channels in LTE, it may bepossible to have less frequency diversity. For example, in sending anACK/NACK report in UTRAN LTE, it may be possible to use distributedtransmission of the 10 repetitions. However, this may impact manyphysical resource blocks that could be used for data transmission, andthere may be a need to reduce overhead. For example, using an addedfading margin of 3 dB, about 4 sub-carriers (0.5 ms) per ACK/NACK reportmay be needed in order to obtain the same uplink coverage as is obtainedin WCDMA/HSDPA. Therefore, according to an exemplary embodiment of thepresent invention, a physical resource block (PRB) defined as having 12sub-carriers, it is possible to fit three ACK/NACK reports into thespace corresponding to a single PRB.

For example, if there is a mixture of VoIP (Voice over InternetProtocol) and HTTP (Hypertext Transfer Protocol) transmissions occurringwithin a cell, it may be necessary to multiplex between a few to quitemany packets every subframe, for example between 2-10 when using anopportunistic scheduler. Therefore, in the worst-case, spacecorresponding to four PRBs should be allocated, but on average lessspace may be allocated. Moreover, it may be possible to limit thescheduling flexibility in order to fix the number of multiplexed packetsevery transmission time interval (TTI). The same consideration may alsobe taken when dealing with RRC, SID TCP ACK, and TCP KAM messages.

According to an exemplary embodiment of the present invention uplinkcontrol signalling, for example ACK/NACK), may be setup as follows.Uplink control channel boundaries for every user are contained within asingle PRB. Therefore, when uplink control is not needed (e.g. threeinstances), the PRB can be immediately used for scheduled transmissionin the uplink. For scheduled transmissions, the allocated physicalresource for ACK/NACK in the uplink is hard-coded to the allocation indownlink (e.g. allocation specific). In this exemplary embodiment theeNodeB may be able to plan ahead in physical resource allocation.

The approach is exemplified in FIG. 2. In the example as shown in FIG.1, two PRBs are allocated to control signalling, and a total of 6ACK/NACK reports can fit within the allocated area. When a user, i.e.UE, is allocated in downlink, the user knows which of the 6 dedicatedcontrol resources it must use based on its order in the allocationtable. For persistent or non-scheduled allocations, the mapping betweendownlink packet and associated uplink resource may be given by higherlayer (or alternative L1/L2) signaling. Here L1 and L2 are air interfaceLayers 1 and 2. Layer 1 is known as the physical layer and Layer 2 adata link layer which comprises two sublayers: a media access control(MAC) and a logic link control (LLC) sublayers. This L1/L2 signaling isreferred to as some control signaling means, which are located below theRRC layer. With this L1/L2 signaling, it is possible to have controlmessages transmitted by the MAC, which would then be in control of thecontrol signaling resource for persistent allocations.

The scheme illustrated in FIG. 2 is useful in reducing the fadingmargin. If needed, a user equipment terminal (UE) can detect from theallocation table (uplink allocation transmitted in downlink) if thecontrol channel PRBs are scheduled and then “ACK/NACK control channels”may be defined according to preset or predetermined rules. For example,if a second control PRB as shown in FIG. 3 is suddenly allocated fordata transmission, the UE would know there are now just 3 availablecontrol channels for the ACK/NACK report, and that distributedtransmission would not be possible. As also shown in FIG. 3, when thesecond PRB is not allocated, then there are 6 ACK/NACK “spaces”distributed over the two PRBs.

A method according to this exemplary embodiment is shown in FIG. 6. Themethod may include a step S20 of setting uplink control channelboundaries within a physical resource block (PRB). For example, FIG. 2shows dedicated control channels within the PRB for ACK/NACK reports.The method may also include a step S21 of deciding whether uplinkcontrol is needed. If uplink control is needed, then the method includesa step S23 of using control signalling space for uplink control.However, if it is determined that uplink control is not needed, i.e.there is available control signalling space, then the method may includea step S22 of allocating scheduled data transmission to the physicalresource blocks. In that case, the method may further include a step S24of hard coding the allocated physical resources for ACK/NACK reports inthe uplink to allocation in the downlink.

In an exemplary embodiment of the invention, the eNodeB may allocateuplink resources for ACK/NACK reports according to the worst-casemultiplexing requirements, and may also consider the probability ofdata-non-associated ACK/NACK, i.e. ACK/NACK reports that are notpiggy-backed to data transmissions. For example, if the eNodeB assumes amultiplexing limit per subframe of 6 (including both semi-static andscheduled transmission), it needs to allocate two PRBs for signaling.

According to an exemplary embodiment of the present invention, theeNodeB can dynamically use parts of the space allocated for uplinkACK/NACK control (or other needed control on dedicated channel) forscheduling user data in the uplink when the eNodeB knows that thiscontrol signaling space will not be used by any user, i.e. any userequipment terminals (UEs), in a cell served by the eNodeB. For example,if only 1-3 users are multiplexed in a certain downlink subframe, theeNodeB can schedule data transmissions in the second PRB, which has beenallocated for control signalling as shown in FIG. 2, for the uplinksubframe where the ACK/NACK reports would normally be sent.

For example, FIG. 4 shows the allocation in downlink, taking intoconsideration how many users and/or packets are multiplexed within eachsubframe. FIG. 4 also shows the processing time of the UE and when theACK/NACK report associated with a certain subframe need be transmittedfrom each of the receiving UE. In the example as shown in FIG. 4,maximally 8 packets are multiplexed within a subframe and this requires3 control PRBs for a maximum PRB allocation. FIG. 4 shows the actualneed of PRBs for control information below the uplink allocation boxes.In the mapping of semi-static users to the control PRBs, the usersshould be grouped such that they do not prevent freeing of control PRBs.For example, it may not be efficient to allocate persistent users todifferent control PRBs. It is understood that semi-static users areusers that are allocated resources in a semi-static manner, i.e. theyare allocated resources once, and then this allocation is valid for acertain period of time, or until the resource is taken away again. Forexample, one persistent allocation pattern would be to have a userallocated a resource every 10^(th) TTI. Accordingly, both the UE and theeNodeB know when the resource is allocated for the user, and there is noneed to use resource allocation overhead for this user. However, asthese users are not known by other scheduled users, these semi-staticallocated users may be treated differently.

FIG. 5 shows an exemplary method according to an embodiment of thepresent invention. The method shown in FIG. 5 may be carried out in aeNodeB. In the method, the eNodeB may conduct downlink packet schedulingfor a sub-frame, for example sub-frame ‘n,’ in step S10. The eNodeB maythen record the number of users and/or packets multiplexed within thedownlink sub-frame ‘n,’ including semi-static allocations in step S11.The eNodeB may then predict how many ACK/NACK reports are expected fromthe users/user equipment terminals (UEs) in step S12. For delayed uplinkallocation, the eNodeB may then calculate how much dedicated resourcespace is needed for the ACK/NACK reports in step S13. In calculating theamount of dedicated resource space required, the eNodeB may take intoconsideration when the ACK/NACK reports will be transmitted, and whethersome of the ACK/NACK reports can be piggy-backed to uplink datatransmission for some of the users/UEs in a data-associated controlsignaling scheme.

For example, if there are k1 scheduled downlink users and k2persistently scheduled downlink users, there would be k=k1+k2 scheduledusers for sub-frame ‘n’, who would need the control signaling of theACK/NACK reports in the uplink. If persistent scheduling is notimplemented in downlink, then k2 is ‘0’. Since uplink and downlinkallocations are disconnected/uncorrelated, there would be m=m1+m2allocations in the uplink, if there is piggy-backed ACK/NACK signaling.Here m1 denotes scheduled users and m2 denotes persistently scheduledusers. If m3 uplink users, with m3 being a subset of the m, are able tocarry their own uplink control signaling, then m4 users (m4=m−m3) willhave to transmit their ACK/NACK signaling using data-non-associatedtransmission. Knowing the number of data-non-associated users within onePRB, it is possible to calculate how many uplink resources need bereserved for the control signaling. Accordingly, the method shown inFIG. 5 may also include a step S14 of allocating users in the uplink inunused ‘control signaling reserved’ PRBs based on how many uplinkresources are needed to be reserved for the control signalling.

Depending on how the mapping scheme is devised, it is possible to adjustthe probabilities of freeing ACK/NACK resources also considering thedata-associated ACK/NACKs.

When an eNodeB is used to schedule users on a shared channel in atransmission time interval (TTI), the eNodeB allocates the uplinkphysical resources for data-non-associated control signaling based onthe current amount of the physical resources for downlink transmission,or the allocation history of the downlink transmission. The amount ofphysical resources for downlink transmission is determined at leastpartly based on the number of users, i.e. user equipment terminals,and/or the number of packets multiplexed within a downlink subframe in aphysical resource block (PRB). The eNodeB is also adapted to allocateuplink physical resources for data transmission based on amount ofphysical resources allocated for transmission of data-non-associatedcontrol signaling.

For delayed uplink allocation, the amount of allocated physicalresources for data-non-associated control signaling is also estimatedbased on whether the data-non-associated control signaling can bepiggy-backed to uplink data transmission. The users for which the amountof uplink physical resources for data-non-associated control signalingis allocated include users in semi-static locations.

FIG. 7 shows some components of an apparatus 11 that may be included ina network element, such the eNode B discussed in relation to exemplaryembodiments of the present invention. The apparatus may include aprocessor 22 for controlling operation of the device, including allinput and output. The processor 22, whose speed/timing is regulated by aclock 22 a, may include a BIOS (basic input/output system) or mayinclude device handlers for controlling user audio and video input andoutput as well as user input from a keyboard. The BIOS/device handlersmay also allow for input from and output to a network interface card.The BIOS and/or device handlers also provide for control of input andoutput to a transceiver (TRX) 26 via a TRX interface 25 includingpossibly one or more digital signal processors (DSPs), applicationspecific integrated circuits (ASICs), and/or field programmable gatearrays (FPGAs). The TRX enables communication over the air with anothersimilarly equipped communication terminal. The apparatus 11 may alsoinclude volatile memory, i.e. so-called executable memory 23, and alsonon-volatile memory 24, i.e. storage memory. The processor 22 may copyapplications (e.g. a calendar application or a game) stored in thenon-volatile memory into the executable memory for execution. Theprocessor functions according to an operating system, and to do so, theprocessor may load at least a portion of the operating system from thestorage memory to the executable memory in order to activate acorresponding portion of the operating system. Other parts of theoperating system, and in particular often at least a portion of theBIOS, may exist in the communication terminal as firmware, and are thennot copied into executable memory in order to be executed. The bootingup instructions are such a portion of the operating system.

Still referring to FIG. 7, the apparatus 11 may also include a scheduler15 for scheduling downlink packets in a sub-frame. The apparatus 11 mayfurther include a recorder 13 for recording the number of users and/orpackets multiplexed within the sub-frame. The apparatus 11 may alsoinclude a prediction module 14 that may be responsive to the recordednumber of multiplexed users and/or packets for predicting a number ofexpected ACK/NACK reports. The apparatus 11 may also include adeterminer 12 that can be responsive to the predicted number of expectedACK/NACK reports for determining how much dedicated resource space isrequired for the expected ACK/NACK reports. The apparatus 11 may furtherinclude an allocation unit for allocating users/UEs to the unusedphysical resources, i.e. unused PRBs.

The functionality described above (for both the radio access network andthe UE) can be implemented as software modules stored in a non-volatilememory, and executed as needed by a processor, after copying all or partof the software into executable RAM (random access memory).Alternatively, the logic provided by such software can also be providedby an ASIC (application specific integrated circuit). In case of asoftware implementation, the invention can be provided as a computerprogram product including a computer readable storage structureembodying computer program code—i.e. the software—thereon for executionby a computer processor.

It is to be understood that the above-described arrangements are onlyillustrative of the application of the principles of the presentinvention. Numerous modifications and alternative arrangements may bedevised by those skilled in the art without departing from the scope ofthe present invention.

What is claimed is:
 1. A method, comprising: determining an amount ofphysical resources for downlink transmission; predicting a number ofexpected reports based at least on the determined amount of physicalresources for downlink transmission; and allocating uplink physicalresources for transmission of data-non-associated control signalingbased at least on the amount of physical resources for downlinktransmission; wherein the amount of physical resources for downlinktransmission comprises an amount of downlink control signaling.
 2. Themethod of claim 1, wherein determining the amount of physical resourcesfor downlink transmission is at least partly based on number of userequipment terminals multiplexed within a downlink subframe in a physicalresource block.
 3. The method of claim 1, wherein determining the amountof physical resources for downlink transmission is at least partly basedon a number of packets multiplexed within a downlink subframe in aphysical resource block.
 4. The method of claim 1, further comprising:allocating uplink physical resources for data transmission based atleast on the amount of uplink physical resources allocated fortransmission of data-non-associated control signaling.
 5. The method ofclaim 1, wherein determining the amount of physical resources fordownlink transmission is based on whether the data-non-associatedcontrol signaling is at least partly incorporated into uplink datatransmission.
 6. The method of claim 1, wherein the amount of physicalresources for downlink transmission comprises physical resourcesallocated for current transmission.
 7. The method of claim 1, whereinthe amount of physical resources for downlink transmission comprisesphysical resources allocated for past transmission.
 8. The method ofclaim 2, wherein the user equipment terminals include user equipmentterminals in semi-static locations.
 9. An apparatus, comprising: adeterminer for determining an amount of physical resources for downlinktransmission; a prediction module for predicting a number of expectedreports based at least on the determined amount of physical resourcesfor downlink transmission; and an allocation unit for allocating uplinkphysical resources for transmission of data-non-associated controlsignaling based at least on the amount of physical resources fordownlink transmission; wherein the amount of physical resources fordownlink transmission comprises an amount of downlink control signaling.10. The apparatus of claim 9, further comprising a recorder forrecording a number of user equipment terminals multiplexed within adownlink subframe in a physical resource block, and wherein thedeterminer is responsive to the number of multiplexed user equipmentterminals for determining the amount of physical resources for downlinktransmission.
 11. The apparatus of claim 9, further comprising arecorder for recording a number of packets multiplexed within a downlinksubframe in a physical resource block, and wherein the determiner isresponsive to the number of multiplexed packets for determining theamount of physical resources for downlink transmission.
 12. Theapparatus of claim 9, wherein the allocation unit is configured toallocate uplink physical resources for data transmission based at leaston the amount of uplink physical resources allocated for transmission ofdata-non-associated control signaling.
 13. The apparatus of claim 9,wherein the determiner is configured to determine the amount of physicalresources for downlink transmission based on whether thedata-non-associated control signaling is at least partly incorporatedinto uplink data transmission.
 14. The apparatus of claim 9, wherein theamount of physical resources for downlink transmission comprisesphysical resources allocated for current transmission.
 15. The apparatusof claim 9, wherein the amount of physical resources for downlinktransmission comprises physical resources allocated for pasttransmission.
 16. The apparatus of claim 10, wherein the user equipmentterminals include user equipment terminals in semi-static locations. 17.The apparatus of claim 10, wherein uplink control channel boundaries foreach of the user equipment terminals are allocated within boundaries ofa single physical resource block.
 18. The apparatus according to claim9, further comprising a scheduler for scheduling downlink packets.
 19. Asystem, comprising: a determiner for determining an amount of physicalresources for downlink transmission; a prediction module for predictinga number of expected reports based at least on the determined amount ofphysical resources for downlink transmission; an allocation unit forallocating uplink physical resources for transmission ofdata-non-associated control signaling based at least on the amount ofphysical resources for downlink transmission; and at least one userequipment terminal responsive to the allocation of uplink physicalresources for transmission of data non-associated control signaling forproviding control signaling according to the allocation; and wherein theamount of physical resources for downlink transmission comprises anamount of downlink control signaling.